Atrial fibrillation (AF) is a common complication of cardiac surgery, occurring in 10-40% of patients. Recent studies show post-cardiac surgery AF to be associated with greater morbidity and poorer long-term survival. The increased age and risk profile of patients receiving CABG as percutaneous coronary intervention has gained popularity for 'routine' revascularizations, makes a formal investigation of the effectiveness of optimal prevention and management of new-onset post-CABG AF and their impact on long- term survival imperative. Since the Society of Thoracic Surgeons (STS) database does not contain detailed information about prophylaxis and management of post-CABG AF, such a study requires access to supplemental data. Objective: The proposed study seeks to evaluate the effectiveness of the prophylaxis and management strategies for new-onset AF following isolated CABG and their impact on long-term survival (>15 years). Methods: The proposed project is a large multicenter observational study which will include 32,420 consecutive patients without pre-operative AF who underwent isolated CABG between 1/1/1997 and 12/31/2008 at Baylor University Medical Center (Dallas, TX), Emory University (Atlanta, GA), University of Virginia (Charlottesville, VA), and Washington University (St. Louis, MO) using data from the STS database, patient medical records, administrative data, and the Social Security Administration Death Master File. Aims: 1) to assess the association between optimal prophylaxis (as defined by the ACC/AHA/ESC and ACCP guidelines) and new-onset post-CABG AF; 2) to assess the association between new-onset post- CABG AF and long term survival (over 15 years), taking into account use (or non-use) of optimal AF management (as defined by the ACC/AHA/ESC and ACCP guidelines); 3) to augment the STS database with pre-, intra-, post-operative (including pharmacological management prior to admission and during hospitalization, anesthesia, clinical and non-clinical patient characteristics, and procedural factors), and long-term survival data (over 15 years) and create a comprehensive registry for research; and 4) to rigorously describing the epidemiology of new-onset post-CABG AF in terms of time, type, and duration of AF in a large population-based setting. Significance: Results will support development of new and more effective strategies to prevent and manage post-CABG AF and will ultimately change current guidelines. With the aging of the overall United States population and the population undergoing CABG, post-CABG AF incidence is expected to increase - making rigorous research data about how best to reduce the burden of this common complication a public health priority. Results will be applicable to >100,000 people in the United States and >1.5 million people worldwide annually.